CVE-2026-4634
Full vulnerability record from the local CVENow database.
Description
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-04-02 13:16:27.027000
Last modified
2026-10-26 21:10:00.170000
View original CVE JSON
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"lastModified": "2026-10-26T21:10:00.170",
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"value": "A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server."
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"value": "Se encontró un defecto en Keycloak. Un atacante no autenticado puede explotar esta vulnerabilidad enviando una solicitud POST especialmente diseñada con un parámetro ’scope’ excesivamente largo al endpoint de token de OpenID Connect (OIDC). Esto conduce a un alto consumo de recursos y tiempos de procesamiento prolongados, lo que finalmente resulta en una denegación de servicio (DoS) para el servidor Keycloak."
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